1. Field of the Invention
The invention is related to the field of robotics systems, and in particular, to the calibration of a robotics system by projecting a laser through the holes of a plate onto a laser detection surface from a plurality of calibration positions.
2. Statement of the Problem
Robotics systems are required to position objects relative to one another with extreme precision. In the field of complex circuitry testing, robotics systems must be able to position test probes within 0.001 of an inch of a point on a printed circuit board. Robotics systems are comprised of mechanical components, electrical components, and software components. These components each operate within individual tolerances that result in errors. The errors combine to degrade overall system performance when positioning objects. The robotics system can be designed so the combination of errors does not exceed the overall system tolerance, but this design technique is a complex undertaking. The resulting robotics system generally operates somewhere under the tolerance, but the actual accuracy of the robotics system is not measured and remains unknown.
An operational robotics system is difficult to calibrate when the robotics system fails to meet the overall system tolerance. System failure often results from a complex combination of non-linear errors. For example, software components round numerical values. Servo control electronics have imperfect response characteristics at various frequencies. Mechanical components lose performance when extended to more distant operating areas. Together, the combination of these errors is difficult to analyze and control when attempting to bring an entire robotics system within an overall system tolerance.
Prior techniques for calibrating a robotics system fail to measure the precision performance of the robotics system when it actually positions objects in an operational area. These systems also fail to generate corrective factors to correct repeated positioning errors. The systems also fail to incorporate the correction factors into the robotics system to improve precision performance in the field.